Intravascular filter retrieval device having an actuatable dilator tip

ABSTRACT

A filter retrieval device having an actuatable dilator tip for retrieval of an intravascular filter from a body lumen is disclosed. An outer shaft coupled to a distal sheath is advanced along a filter wire to desired point within the vasculature. An intravascular filter such as a distal protection filter can be advanced along the filter wire to a point distal a lesion to collect debris dislodged during a medical procedure. Disposable in part within the distal sheath is an actuatable dilator tip adapted to retrieve the filter at least in part within the distal sheath. Actuation of the dilator tip may be accomplished by any number of means, including a resilient member such as a spring coil, or by a reduced inner diameter portion disposed on the distal sheath adapted to engage a plurality of recessed surfaces disposed on the dilator tip.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.10/083,810 filed Feb. 27, 2002, which claims the benefit of U.S.Provisional Application Ser. No. 60/272,657, filed on Mar. 1, 2001.

FIELD OF THE INVENTION

The present invention relates generally to the field of embolicprotection devices. More specifically, the present invention pertains toretrieval devices for intravascular filters.

BACKGROUND OF THE INVENTION

Intravascular filters such as embolic protection filters are generallyplaced within a body lumen, such as an artery or vein, downstream of asite where a therapeutic device will be used. Examples of proceduresemploying such filters include angioplasty, atherectomy, thrombectomyand stent placement. These procedures typically involve transluminallyinserting and delivering within the artery or vein, a filter wire andfilter to a location distal a coronary lesion. Once in place, atherapeutic device such as an angioplasty balloon or an atherectomycatheter can be advanced to the site of the lesion to perform theprocedure. During the procedure, embolic material such as plaque orthrombus become dislodged from the walls of the body lumen, and flowdownstream where they are collected by the filter. After the procedureis performed, the therapeutic device and filter containing the debris,if any, can be removed from the body.

SUMMARY OF THE INVENTION

The present invention relates generally to the field of embolicprotection devices. More specifically, the present invention pertains toretrieval devices for intravascular filters. In one embodiment inaccordance with the present invention, a filter retrieval deviceincludes a distal sheath and an outer shaft extending proximallytherefrom. A dilator tip is biased toward the distal end of the distalsheath by a resilient member. In one particular implementation, theresilient member may include a spring coil having one or more coilshelically disposed along the filter wire. In an alternativeimplementation, the resilient member may include a spring having one ormore struts longitudinally disposed along the filter wire. In use, thefilter retrieval device is advanced along the filter wire until thedilator tip contacts a proximal filter stop. The filter retrieval deviceis then further advanced such that the filter collapses and is containedat least in part within the distal sheath.

In a similar embodiment, a filter retrieval device comprises a distalsheath and an outer shaft extending proximally therefrom, an actuatabledilator tip, and an inner shaft disposed at least in part within thelumen formed by the distal sheath. As with the aforementionedembodiment, the dilator tip is biased toward the distal end of thedistal sheath by a resilient member such as a spring coil. The innershaft may have a length substantially similar to the length of the outershaft. Alternatively, the inner shaft may have a length substantiallyshorter than the length of the outer shaft. In the latter case, anexchange port can be disposed on the outer shaft to permit singleoperator advancement of the filter retrieval device.

In another embodiment of the present invention, a filter retrievaldevice comprises a distal sheath, a shaft, and a dilator tip slidablydisposable along a filter wire. The distal sheath has a reduced innerdiameter portion adapted to engage a recessed surface disposed on aportion of the dilator tip. In one particular implementation, therecessed surface includes a first recessed surface disposed on aproximal portion of the dilator tip, and a second recessed surfacedisposed on the dilator tip distal the first recessed surface. Prior touse, the operator attaches the dilator tip to the distal sheath byengaging the reduced inner diameter portion along the first recessedsurface. To retrieve the filter, the operator then advances the devicealong the filter wire until the distal end of the dilator tip contactsthe filter stop. Once the dilator tip is attached to the filter stop,further advancement of the dilator tip causes the reduced inner diameterportion of the distal sheath to engage the second recessed surface onthe dilator tip. Continued advancement of the dilator tip causes thefilter to retract at least in part within the distal sheath. A thirdrecessed surface disposed on the dilator tip distal the second recessedsurface may be utilized to provide the operator with tactile feedbackthat the filter has been retracted into the distal sheath a sufficientdistance to permit removal from the body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a filter retrieval device inaccordance with the present invention advanced to a distal protectionfilter;

FIG. 2 is a cross-sectional view of the device of FIG. 1, wherein thecatheter is advanced at least in part over the filter;

FIG. 3 is a cross-sectional view of a second embodiment of a filterretrieval device in accordance with the present invention advanced to adistal protection filter;

FIG. 4 is a cross-sectional view of the device of FIG. 3, wherein thecatheter is advanced at least in part over the filter;

FIG. 5 is a cross-sectional view of another embodiment of a filterretrieval device in accordance with the present invention advanced to adistal protection filter;

FIG. 6 is a cross-sectional view of the device of FIG. 5, wherein thecatheter is advanced at least in part over the filter;

FIG. 7 is a plan view of a filter retrieval device in accordance withthe present invention, wherein the device includes a plunger assembly;

FIG. 8 is a plan view of the filter retrieval device of FIG. 7, whereinthe device is advanced at least in part over the filter;

FIG. 9 is a cross-sectional view of a filter retrieval device inaccordance with another embodiment of the present invention having aplunger assembly;

FIG. 10 is a cross-sectional view of the filter retrieval device of FIG.9, wherein the catheter is advanced at least in part over the filter;

FIG. 11 is a cross-sectional view of a filter retrieval device inaccordance with the present invention advanced to a distal protectionfilter;

FIG. 12 is a cross-sectional view of the device of FIG. 11, wherein thecatheter is advanced at least in part over the filter;

FIG. 13 is a cross-sectional view of a filter retrieval device inaccordance with the present invention employing a snap-fit mechanism;

FIG. 14 is a cross-sectional view of the filter retrieval device of FIG.13, wherein the device is advanced at least in part over the filter;

FIG. 15 is a cross-sectional view of another embodiment of a filterretrieval device in accordance with the present invention employing asnap-fit mechanism;

FIG. 16 is a cross-sectional view of the filter retrieval device of FIG.15, wherein the catheter is advanced at least in part over the filter;

FIG. 17 is a cross-sectional view of a filter retrieval device inaccordance with yet another embodiment of the present invention, whereinthe device is in a first position advanced to a distal protectionfilter;

FIG. 18 is a cross-sectional view of the filter retrieval device of FIG.17, wherein the device is in a second position attached to the filter;

FIG. 19 is a cross-sectional view of the filter retrieval device of FIG.17, wherein the device is in a third position fully advanced over thefilter;

FIG. 20 is a cross-sectional view of a guide catheter, filter wire anddistal protection filter disposed within a body lumen;

FIG. 21 is a cross-sectional view illustrating a second step ofadvancing and attaching a dilator to the filter;

FIG. 22 is a cross-sectional view illustrating a third step of advancingan outer sheath along the guidewire and dilator and collapsing thefilter therein;

FIG. 23 is a cross-sectional view of guide catheter, filter wire anddistal protection filter disposed within a body lumen;

FIG. 24 is a cross-sectional view illustrating a second step ofadvancing and attaching a dilator to the filter;

FIG. 25 is a cross-sectional view illustrating a third step of advancingan outer sheath along the guidewire and dilator and collapsing thefilter therein;

FIG. 26 is a cross-sectional view illustrating a fourth step of removingthe dilator, guidewire and collapsed filter from the body;

FIG. 27 is a cross-sectional view illustrating a fifth step of insertinga second guidewire into the patient through the guide catheter and outersheath.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings wherein like reference numerals refer tolike elements throughout the several views, FIG. 1 is a cross-sectionalview of a filter retrieval catheter 10 in accordance with the presentinvention. Filter retrieval catheter 10 includes an outer shaft 14 and agenerally cylindrical distal sheath 12 extending distally thereof.Distal sheath 12 defines a lumen 40 adapted to contain an intravascularfilter such as the distal protection filter 22 shown in FIG. 1, oncecollapsed.

As shown in FIG. 1, catheter 10 has been advanced along a filter wire 20to filter 22 disposed at the distal end of filter wire 20. Filter wire20 includes a distal tip 24 which can be a spring tip. A filter stop 26is disposed on filter wire 20 proximate and proximal the filter 22.Although the particular distal tip 24 shown in FIG. 1 is substantiallystraight, an arcuate or “J” shaped distal tip (not shown) can beutilized to facilitate steering and tracking during advancement offilter wire 20 through the body.

Catheter 10 further includes an inner shaft 16 disposable at least inpart within lumen 40 formed by distal sheath 12. Inner shaft 16 exitscatheter 10 proximally at opening 18. In the particular embodiment shownin FIG. 1, inner shaft 16 has a length substantially shorter than thelength of outer shaft 14 to enable single operator advancement ofcatheter 10 within the body.

Also disposed within distal sheath 12 is a dilator tip 28 and a springcoil 30. Dilator tip 28 has a generally circular cross section andconical-shaped distal end. Dilator tip 28 is biased at least in part outof the distal end of distal sheath 12 by spring coil 30. In theparticular embodiment shown in FIG. 1, the proximal end of spring coil30 is bonded to a portion of inner shaft 16. The distal end of springcoil 30, in turn, is bonded to dilator tip 28 at a distal bonding region32.

In use, for example, filter 22 is positioned in a body vessel distallyof a location where a therapeutic device is to be used. In anapplication, filter 22 can be positioned distally of a coronary lesion.A therapeutic device such as an angioplasty catheter can be advancedover filter wire 20 to the lesion. Coronary angioplasty can be performedby the angioplasty catheter and debris dislodged by the procedure can becaptured in filter 22. The angioplasty catheter can then be withdrawn.Catheter 10 can then be advanced over filter wire 20 until dilator tip28 contacts filter stop 26. Catheter 10 can then be further advancedsuch that spring coil 30 is compressed and dilator tip 28 is drawn intolumen 40 of distal sheath 12. Catheter 10 is further advanced untilfilter 22 is disposed at least in part within distal sheath 12, as shownin FIG. 2. Then catheter 10, filter wire 20, filter 22 and the collecteddebris can then be removed from the vessel lumen.

In an alternative embodiment to that shown in FIGS. 1-2, a filterretrieval device having an inner shaft with a length substantiallysimilar to the length of the outer shaft may be utilized. For example,in the particular embodiment shown in FIG. 3, the proximal end of innershaft 116 terminates at or near the proximal end of outer shaft 114.Openings 142 and 118 are provided on inner shaft 116 and outer shaft114, respectively, to permit single operator advancement of thecatheter. As with the previous embodiment, a spring coil 130 is bondedto a portion of inner shaft 116, and to bonding region 132 on dilatortip 128.

A locking hub 144 disposed at or near the proximal end of the catheteris further provided to prevent relative motion between inner shaft 116and outer shaft 114. Locking hub 144 may be attached to the inner andouter shafts by adhesive, solder or other attachment means, or by areleasable lock mechanism (not shown).

To retrieve the filter 22, outer shaft 114 is locked to inner sheath 116by locking hub 144. Catheter 110 is advanced to a desired site in thebody proximate and proximal filter 22. The catheter is then furtheradvanced until dilator tip 128 attaches to filter stop 26. Once attachedto filter stop 26, dilator tip 128 is retracted proximally, causingfilter 22 to collapse at least in part within lumen 140 formed by distalsheath 112, as shown in FIG. 4.

FIG. 5 is a cross-sectional view of another embodiment of a filterretrieval device in accordance with the present invention. Catheter 210includes a generally cylindrical distal sheath 212 and an outer shaft214 extending proximally therefrom. Outer shaft 214 includes a sideopening 218 to enable single operator advancement of catheter 210 withinthe body. A dilator tip 228 is disposable at least in part within thelumen 240 formed by distal sheath 212.

As shown in FIG. 5, Dilator tip 228 is biased at least in part distallyfrom distal sheath 212 by a spring coil 230. The distal end of springcoil 230 can be bonded to dilator tip 228 at a dilator bonding region232. A tapered portion 236 disposed on the catheter prevents spring coil230 from retracting proximally from distal sheath 212, when actuated.

Catheter 210 is used in a manner similar to that of catheters 10 and110. For example, as illustrated in FIG. 6, filter 22 can be collapsedand drawn into distal sheath 212 in a manner similar to that shown anddescribed with respect to FIGS. 2 and 4.

FIG. 7 is a plan view of another exemplary embodiment of the presentinvention employing a plunger assembly. Catheter 310 includes a distalsheath 312 and an outer shaft 314 extending proximally therefrom. Adilator tip 328 and spring coil 330 are disposed within the distalsheath 312, similar to the embodiment shown in FIGS. 5-6.

An inner shaft 316 having a proximal end 346 and a distal end 348 isdisposed within outer shaft 314 and distal sheath 312. The distal end348 of inner shaft 316 may be attached to the proximal end of dilatortip 328 by adhesive or other attachment means.

Catheter 310 further includes a plunger assembly comprising a tubularmember 352 defining a lumen 350, and a plunger 354 formed by enlargeddiameter portion on the proximal end 346 of inner shaft 316. Plunger 354is adapted to slide along filter wire 20 within lumen 350 formed bytubular member 352. A shaft 356 extending proximally from tubular member352 is further disposed in part within lumen 350. A distal section 358of shaft 356 is crimped in a smiley-face configuration to permit thefilter wire 20 to exit catheter 310 through opening 360, and to act as aproximal stop for plunger 354. The proximal end of outer shaft 314,which extends proximally into lumen 350 formed by tubular member 352, isadapted to act as a distal stop for plunger 354.

In use, spring coil 330 biases the dilator tip 328 at least in pandistally from distal sheath 312. To retrieve the filter, catheter 310 isadvanced to a point along the filter wire 20 proximate and proximalfilter stop 26. Catheter 310 is further advanced until dilator tip 328attaches to filter stop 26. Once attached, filter wire 20 is retractedproximally, causing plunger 354 to slide proximally within tubularmember 352, and filter 22 to collapse at least in part within distalsheath 312, as shown in FIG. 8. The crimped distal end 362 of shaft 356acts as a proximal stop for plunger 354. When plunger 354 abuts distalend 362, the operator is prevented from retracting filter 22 furtherinto distal sheath 312, thus providing the operator with tactilefeedback that filter 22 is collapsed within distal sheath 312.

FIG. 9 illustrates another exemplary embodiment in accordance with thepresent invention. In the particular embodiment shown in FIG. 9, springcoil 430 is disposed within tubular member 452 proximal an inner shaft416. Inner shaft 416 has a proximal end 446 and a distal end 448. Anenlarged diameter portion disposed on the proximal end 446 of innershaft 416 forms a plunger 454. The distal end 448 of inner shaft 416 isattached to dilator tip 428.

Spring coil 430 is adapted to bias the dilator tip 428 distally fromdistal sheath 412. As with the embodiment illustrated in FIGS. 8-9, thecrimped distal end 462 of shaft 456 is adapted to hold spring coil 430in partial compression, and to prevent spring coil 430 from retractingproximally.

To retrieve the filter, catheter 410 is advanced along the filter wire20 until dilator tip 428 contacts filter stop 26. Further advancement ofcatheter 410 causes the filter 22 to collapse within the lumen 440 ofdistal sheath 412, as shown in FIG. 10. Then the catheter containingfilter wire 20, filter 22 and the debris can be removed from the body.

FIGS. 11 and 12 are cross-sectional views of a filter retrieval devicein accordance with yet another embodiment of the present invention.Catheter 510 includes a cylindrical distal sheath 512 coupled to anouter shaft 514 distally thereof Disposable at least in part withinlumen 540 of distal sheath 512 is a dilator tip 528 similar to thatdepicted in FIGS. 9-10. Dilator tip 528 is biased at least in partdistally from distal sheath 512 by a spring coil 530.

Spring coil 530 is formed by a portion of a wire 560 that has a proximalend 562 and a distal end 564. The proximal end 562 of wire 560 isattached to outer shaft 514 at or near opening 518. Wire 560 issubstantially straight from proximal end 562 to point 566, and ishelically disposed about inner shaft 516 from point 566 to distal end564.

In use, when catheter 530 is advanced distally, dilator tip 528 attachesto filter stop 26. Further advancement of the catheter causes filter 22to collapse and retract at least in part into the distal sheath 512, asshown in FIG. 12.

Although the particular embodiments depicted in FIGS. 1-12 utilize ahelically disposed spring coil to bias the dilator tip distally from thedistal sheath, other configurations are possible without deviating fromthe scope of the invention. For example, a spring having one or morestruts disposed longitudinally along the axis formed by the filter wiremay be used to bias the dilator tip distally from the distal sheath. Inyet another example, the spring may comprise an accordion-shapedpolymeric tube adapted to bias the dilator tip distally from the distalsheath.

It is also to be understood that several different materials may beutilized to form the resilient members without deviating from the scopeof the present invention. For example, the spring coil may be comprisedof 304 or 316 grade stainless steel, or may be comprised of a polymericmaterial such as polyethylene (PE), polypropylene (PP),polyvinylchloride (PVC) or polytetrafluoroethylene (PTFE).

FIG. 13 illustrates yet another exemplary embodiment of the presentinvention utilizing a snap-fit mechanism to retrieve the filter. Filterretrieval catheter 610 includes a distal sheath 612 coupled to a shaft614 extending proximally therefrom. Distal sheath 612 defines a lumen640 adapted to carry a filter such as a distal protection filter, oncecollapsed.

Disposable at least in part within lumen 640 is a dilator tip 628.Dilator tip 628 is comprised of a substantially hard material, andincludes several recessed surfaces adapted to permit relative motionbetween the dilator tip 628 and the distal sheath 612. In the particularembodiment shown in FIG. 13, dilator tip 628 includes a first recessedsurface 670 disposed on a proximal portion of dilator tip 628, and asecond recessed surface 672 disposed distally the first recessed surface670, The first recessed surface 670 and second recessed surface 672 areadapted to permit a reduced inner diameter portion 676 disposed ondistal sheath 612 to slide thereon.

The length of the second recessed surface can be varied depending on theactuation length desired. In an application, the length of the secondrecessed surface can be pre-determined to provide a sufficient actuationlength to permit the filter to completely collapse within the distalsheath. This pre-determined length provides the operator with feedbackon the location of the filter within the distal sheath, thus obviatingthe need to resort to more traditional fluoroscopic imaging techniques.

To retrieve the filter, dilator tip 628 is first attached to the distalsheath 612 prior to insertion of the device into the body. In a firstposition shown in FIG. 13, catheter 610 is inserted into the patient andadvanced to the site of the filter to be retrieved. A barb 678 disposedon dilator tip 628 distal the first recessed surface 670 preventsdilator tip 628 from sliding relative to distal sheath 612 duringdelivery. Once catheter 610 has been advanced to the site, and thedistal end of dilator tip 628 abuts filter stop 26, continued retractionof filter wire 20 and/or advancement of the catheter causes the reducedinner diameter portion 674 on the distal sheath 612 to overcome thefrictional force exerted by barb 678. When this occurs, barb 678displaces distally, allowing reduced inner diameter portion 676 toengage the second recessed surface 672. Continued retraction of reducedinner diameter portion 676 along the second recessed surface 672 drawsfilter 22 into delivery sheath 612, as shown in FIG. 14. Then thecatheter containing the filer wire 20, collapsed filter 22 and collecteddebris can be withdrawn from the body.

FIG. 15 is a cross-sectional view of another embodiment in accordancewith the present invention. Similar to the embodiment illustrated inFIGS. 13-14, catheter 710 includes a distal sheath 712 coupled to ashaft 714 (not shown) extending proximally therefrom. Distal sheath 712defines a lumen 740 adapted to carry a filter such as a distalprotection filter, once collapsed.

In the particular embodiment shown in FIG. 15, distal sheath 712 has areduced inner diameter portion 776 which is adapted to slidably engagethe first recessed surface 770 and second recessed surface 772 ondilator tip 728.

In use, catheter 710 operates in a manner similar to that of catheter610. For example, as illustrated in FIG. 16, filter 22 can be collapsedand drawn into distal sheath 712 in a manner similar to that shown anddescribed with respect to FIG. 14.

In a similar embodiment to that shown in FIGS. 13-16, a filter retrievaldevice having an actuatable dilator tip further comprises a thirdrecessed surface disposed on the dilator tip to provide the operatorwith tactile feedback that the filter is fully drawn into the catheter.As illustrated in FIG. 17, a filter retrieval catheter 810 having anactuatable dilator tip includes a distal sheath 812 coupled to a shaft814 distally thereof, and a dilator tip 828 slidably disposable along afilter wire 20.

Dilator tip 828 includes a first recessed surface 870 disposed on aproximal portion thereof, a second recessed surface 872 disposeddistally the first recessed surface 870, and a third recessed surface874 disposed distally the second recessed surface 872. In anapplication, the length of the second recessed surface 872 can bepre-determined to provide a sufficient actuation length to permit thefilter to completely collapse within distal sheath 812.

To retrieve the filter, dilator tip 828 is attached to the distal sheath812 and inserted into the patient. In a first position shown in FIG. 17,catheter 810 is advanced to a location proximate and proximal a filter22. A barb 878 disposed on dilator tip 828 distal the first recessedsurface 870 prevents dilator tip 828 from sliding relative to distalsheath 812 during delivery. Once catheter 810 has been advanced to thesite, and the distal end of dilator tip 828 abuts filter stop 26,continued retraction of filter wire 20 and/or advancement of thecatheter causes the reduced inner diameter portion 876 on distal sheath812 to overcome the frictional force exerted by barb 878. Continuedretraction of the reduced inner diameter portion 876 in the proximaldirection along the second recessed surface 872 draws filter 22 intodelivery sheath 812, as shown in FIG. 18. A second barb 880 disposeddistally of the second recessed surface 872 is then engaged. When asufficient force is exerted on the second barb 880, barb 880 displaces,allowing reduced inner diameter portion 876 to engage the third recessedsurface 874 as shown in FIG. 19. When the third recessed surface 874 isengaged, continued retraction of dilator tip 828 is prevented, thusinforming the operator that filter 22 has been fully encapsulated withindistal sheath 812.

Referring now to FIGS. 20-27, methods for retrieving an intravascularfilter from a body lumen will now be described. As shown in FIG. 20, aguide catheter 910 having a flared distal end 982 is inserted into thelumen of a patient. A guidewire 20 is inserted through the guidecatheter, and is advanced to a desired site within the patient. Anintravascular filter 22 such as a distal protection filter is thenadvanced along guidewire 20 and placed at or near the distal endthereof. In an application, filter 22 is advanced to a location distal alesion to collect debris dislodged during a therapeutic procedure suchas an angioplasty or atherectomy.

To retrieve filter 22 from the body lumen, a dilator tip 928 is advancedby means of a pushing member 984 along filter wire 20 through guidecatheter 910 to a point proximate and proximal filter 22. As shown inFIG. 21, the physician then further advances dilator tip 928 until itattaches to filter stop 26. Once dilator tip 928 is attached to filterstop 26, an outer sheath 992 is advanced along filter wire 20 anddilator tip 928 over filter 22, causing the filter to collapse withinthe outer sheath as shown in FIG. 22. Then, the dilator tip 928, filterwire 20, filter 22 and collected debris can be removed from the body.

FIGS. 23-27 illustrate an alternative method for retrieving anintravascular filter in accordance with the present invention wherein asecond guidewire is placed within the body. As shown in FIG. 23, aguidewire is inserted into guide catheter 910, and is advanced to adesired location within the body where the procedure is to be performed.Disposed at or near the distal end of guidewire 20 is a filter 22.

Retrieval of the filter 22 from the body lumen proceeds in a mannersimilar to that illustrated in FIGS. 20-22. A dilator tip 928 isadvanced along guidewire 20 by means of a pushing member 984 to a pointproximate and proximal filter stop 26. Continued advancement causes thedilator tip 928 to attach to filter stop 26.

As shown in FIG. 24, once dilator tip 928 is attached to the filter stop26, an outer sheath 992 is advanced along guidewire 20 to a point distalthe proximal end of filter 22, causing the filter to collapse in partwithin the outer sheath. The flanged portion 982 disposed on the distalend of guide catheter 910 is adapted to prevent the proximal end ofouter sheath 992 from exiting the guide catheter 910 distally.

Outer sheath 992 defines a lumen adapted to carry filter 22 in acollapsed state. A marking band (not shown) disposed about a distalportion of outer sheath 992 permits the operator to fluoroscopicallyjudge the location of the outer sheath within the body.

Once filter 22 has been drawn into outer sheath 992, the dilator 928,filter wire 20, filter 22 and collected debris can be retracted throughouter sheath 992 and guide catheter 910 and removed from the patient, asshown in FIG. 26. A second guidewire 920 can be inserted through guidecatheter 910 and outer sheath 992 to the site, as shown in FIG. 27.

Having thus described the embodiments of the present invention, those ofskill in the art will readily appreciate other alternative embodimentsthat may be employed which fall within the scope of the claims attachedhereto. Numerous advantages of the invention covered by this documenthave been set forth in the foregoing description. It should beunderstood that the embodiments of the present invention are exemplaryonly. Changes may be made in details, particularly in matters of shape,size and arrangement of parts without exceeding the scope of theinvention.

1. (canceled)
 2. A filter system, comprising: a filter wire having aproximal end and a distal end; a filter disposed proximal of the distalend of the filter wire; a shaft having a proximal end, a distal end, anda distal sheath disposed at least in part distally thereof, said distalsheath having a reduced inner diameter portion; and a dilator tipslidably disposable along the filter wire, said dilator tip having aplurality of recessed surfaces adapted to engage the reduced innerdiameter portion of said distal sheath.
 3. The filter system of claim 2,wherein said plurality of recessed surfaces includes: a first recessedsurface disposed on a proximal portion of the dilator tip; and a secondrecessed surface disposed on the dilator tip distal said first recessedsurface.
 4. The filter system of claim 3, further comprising a thirdrecessed surface disposed on the dilator tip distal said second recessedsurface.
 5. The filter system of claim 2, wherein the shaft limitsproximal travel of the dilator tip.
 6. The filter system of claim 2,wherein the dilator tip is movable between a distally advanced positionin which the dilator tip extends at least partially beyond a distal endof the distal sheath and a proximally retraced position.
 7. The filtersystem of claim 6, wherein the dilator tip comprises a conical shapeddistal portion.
 8. A device for removing an intravascular filter from abody lumen, comprising; a shaft having a proximal end, a distal end, anda reduced inner diameter portion; and a dilator tip slidably disposablealong a filter wire, said dilator tip having a plurality of recessedsurfaces adapted to engage the reduced inner diameter portion of saidshaft.
 9. The device of claim 8, wherein said recessed surface includes:a first recessed surface disposed on a proximal portion of the dilatortip; and a second recessed surface disposed on the dilator tip distalsaid first recessed surface.
 10. The device of claim 9, furthercomprising a third recessed surface disposed on the dilator tip distalsaid second recessed surface.
 11. The device of claim 8, wherein theshaft comprises an inner shaft having a distal end and a distal sheathextending from the distal end of the inner shaft.
 12. The device ofclaim 11, wherein the reduced inner diameter portion is disposed withinthe distal sheath.
 13. The device of claim 8, wherein the shaftcomprises an inner shaft and an outer shaft, the inner shaft extendingat least partially into the outer shaft, the inner shaft defining thereduced inner diameter portion.
 14. A method for retrieving anintravascular filter from a body lumen, comprising the steps of:providing a filter retrieval device having a distal sheath extendingdistally from a shaft, and a dilator tip slidably disposable along afilter wire, wherein said distal sheath has a reduced inner diameterportion adapted to engage a first recessed surface and a second recessedsurface disposed on said dilator tip; attaching the dilator tip to thedistal sheath in a first position, wherein said reduced inner diameterportion is engaged along said first recessed surface; advancing thefilter retrieval device distally along the filter wire until the distalend of said dilator tip attaches to the filter, retracting the dilatortip to a second position, wherein said reduced inner diameter portionengages said second recessed surface, and wherein said filter isdisposed at least in part within the distal sheath; and removing thefilter retrieval device containing the filter from the body.
 15. Themethod of claim 14, further comprising the steps of providing a dilatortip having a third recessed surface, and further retracting the dilatortip proximally to a third position such that said reduced inner diameterportion engages said third recessed surface.